Electrical and Optical Structural Analysis of Pure Nitrogen RF-CCP}

In this work, 13.56 MHz pure (99.995 {\%}) nitrogen discharges were generated in a stainless steel cylindrical reactor (R$\sim $500 mm, H$\sim $400 mm). Two identical aluminum electrodes with R$\sim $200 mm were placed in the reactor at a 4 cm gap distance. A High-Resolution HR2000 fiber optic spectrometer (200-1100 nm) was connected to the system to do parametrical analyses. The RF power was in the range of 50-200 W and the pressure was in the range of 0.2-0.7 Torr. I detected many nitrogen atomic lines of N, N$^{\mathrm{+\thinspace }}$and N$^{\mathrm{++\thinspace }}$in the UV-Vis-NIR spectral regions. Strong N$^{\mathrm{++}}$ atomic lines (336.3, 379.45 nm) are mainly dominated the spectrum. Two atomic lines (677.28, 773.26 nm) of the N are \textasciitilde four times weaker than that of N$^{\mathrm{++}}$. The atomic lines of the N$^{\mathrm{+\thinspace }}$are \textasciitilde 10 times weaker than that of N$^{\mathrm{++}}$. Also many molecular nitrogen bands, which are the first positive N$_{\mathrm{2}}$ (B-A) system (530-970 nm), the second positive N$_{\mathrm{2}}$ (C-B) system (290-531 nm) and the first negative N$_{\mathrm{2}}^{\mathrm{+}}$ (B-X) system (410-530 nm) are observed. The excitation temperature (T$_{\mathrm{exc}})$ and the electron density (n$_{\mathrm{e}})$ of the N$^{\mathrm{+}}$ and N$^{\mathrm{++}}$ atomic ions were calculated for each discharge condition.